Where would I look to get the most accurate experimental values of parton distribution functions for the proton? I know these functions aren't measured directly, but I'd basically like to find a fit that involves recent experimental data.

I was reading a paper on PDFs which briefly discussed how the theoretical functions are fit to data and included some sample figures, but it dates from 1996 and I'm looking for something more recent.

Thanks... I was really looking for the actual numerical data, so it'd be even better to get an answer with a direct link - but I presume I can get there by following the citations from these papers, so this is helpful.
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David Z♦Apr 14 '11 at 17:37